Re: [PATCH] x86, amd_ucode: Safeguard against #GP

[Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>]

On 5/22/2014 10:56 AM, Andrew Cooper wrote:
> On 22/05/14 16:53, Aravind Gopalakrishnan wrote:
>> On 5/21/2014 5:08 PM, Andrew Cooper wrote:
>>> On 21/05/2014 22:28, Aravind Gopalakrishnan wrote:
>>>> When HW tries to load a corrupted patch, it generates #GP
>>>> and hangs the system. Use wrmsr_safe instead so that we
>>>> fail to load microcode gracefully.
>>>>
>>>> Example on a Fam15h system-
>>>> (XEN) microcode: CPU0 collect_cpu_info: patch_id=0x6000626
>>>> (XEN) microcode: CPU0 size 7870, block size 2586 offset 76 equivID
>>>> 0x6012 rev 0x6000637
>>>> (XEN) microcode: CPU0 found a matching microcode update with version
>>>> 0x6000637 (current=0x6000626)
>>>> (XEN) traps.c:3073: GPF (0000): ffff82d08016f682 -> ffff82d08022d9f8
>>>> (XEN) microcode: CPU0 update from revision 0x6000637 to 0x6000626
>>>> failed
>>>>
>>>> Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
>>> I suspect that you will find with a *very* up-to-date master tree, an
>>> early #GP should result in panic() instead of a hang, following
>>> 279840d5ea646  (If it doesn't I would be interested to know)
>> The console log states 'Panic on CPU0'. But system is basically hung
>> after that.
>> (attached snapshot)
> I refer you to the last line :)
>
> You have "noreboot" on your command line
>

Ah. Okay, Will try again.

Thanks,
-Aravind.